Hustlin' Hank wrote:
....
Well, it could be any of the systems. ...

No matter what, it will take time, effort and a systematic approach to
diagnose his problem. The Gas cap vent is a good start too. Quick and
easy.

Of course it _could_, but one might as well start w/ those that have
some semblance of a resemblance to being at all likely to cause the
observed symptoms. The likely safety interlock system failure modes
don't match at all well...

Gas tank venting is, otoh, worth checking in the short/initial list...

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